Introduce a chip_info structure to parameterize device-specific
properties such as ODR/bandwidth frequency tables, activity/inactivity
timer scale factors, and the maximum ODR value. This refactors the
driver to use chip_info lookups instead of hardcoded values, preparing
the driver to support multiple device variants.

The sampling_frequency and filter_low_pass_3db_frequency available
attributes are switched from custom sysfs callbacks to read_avail()
based handling via info_mask_shared_by_type_available. This enforces
consistent formatting through the IIO framework and makes the values
accessible to in-kernel consumers.

The SPI/I2C probe functions are updated to pass a chip_info pointer
instead of a device name string.

No functional change intended.

Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
---
Changes in v4:
 - Reformat info_mask_shared_by_type to use consistent multi-line
   style matching info_mask_shared_by_type_available.
 - Drop trailing comma from ADXL372_ODR_NUM enum terminator.
 - Drop redundant NULL checks for chip_info in SPI/I2C probe
   functions since match data is always provided.

 drivers/iio/accel/adxl372.c     | 151 ++++++++++++++++++--------------
 drivers/iio/accel/adxl372.h     |  16 +++-
 drivers/iio/accel/adxl372_i2c.c |  10 ++-
 drivers/iio/accel/adxl372_spi.c |  10 ++-
 4 files changed, 112 insertions(+), 75 deletions(-)

diff --git a/drivers/iio/accel/adxl372.c b/drivers/iio/accel/adxl372.c
index 28a8793a53b6..b34b91cae753 100644
--- a/drivers/iio/accel/adxl372.c
+++ b/drivers/iio/accel/adxl372.c
@@ -180,6 +180,7 @@ enum adxl372_odr {
 	ADXL372_ODR_1600HZ,
 	ADXL372_ODR_3200HZ,
 	ADXL372_ODR_6400HZ,
+	ADXL372_ODR_NUM
 };
 
 enum adxl372_bandwidth {
@@ -214,14 +215,35 @@ enum adxl372_fifo_mode {
 	ADXL372_FIFO_OLD_SAVED
 };
 
-static const int adxl372_samp_freq_tbl[5] = {
-	400, 800, 1600, 3200, 6400,
+static const int adxl372_samp_freq_tbl[ADXL372_ODR_NUM] = {
+	[ADXL372_ODR_400HZ] = 400,
+	[ADXL372_ODR_800HZ] = 800,
+	[ADXL372_ODR_1600HZ] = 1600,
+	[ADXL372_ODR_3200HZ] = 3200,
+	[ADXL372_ODR_6400HZ] = 6400,
 };
 
-static const int adxl372_bw_freq_tbl[5] = {
-	200, 400, 800, 1600, 3200,
+static const int adxl372_bw_freq_tbl[ADXL372_ODR_NUM] = {
+	[ADXL372_BW_200HZ] = 200,
+	[ADXL372_BW_400HZ] = 400,
+	[ADXL372_BW_800HZ] = 800,
+	[ADXL372_BW_1600HZ] = 1600,
+	[ADXL372_BW_3200HZ] = 3200,
 };
 
+const struct adxl372_chip_info adxl372_chip_info = {
+	.name = "adxl372",
+	.samp_freq_tbl = adxl372_samp_freq_tbl,
+	.bw_freq_tbl = adxl372_bw_freq_tbl,
+	.num_freqs = ARRAY_SIZE(adxl372_samp_freq_tbl),
+	.act_time_scale_us = 3300,
+	.act_time_scale_low_us = 6600,
+	.inact_time_scale_ms = 13,
+	.inact_time_scale_low_ms = 26,
+	.max_odr = ADXL372_ODR_6400HZ,
+};
+EXPORT_SYMBOL_NS_GPL(adxl372_chip_info, "IIO_ADXL372");
+
 struct adxl372_axis_lookup {
 	unsigned int bits;
 	enum adxl372_fifo_format fifo_format;
@@ -257,8 +279,12 @@ static const struct iio_event_spec adxl372_events[] = {
 	.modified = 1,							\
 	.channel2 = IIO_MOD_##axis,					\
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),			\
-	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |		\
-				    BIT(IIO_CHAN_INFO_SAMP_FREQ) |	\
+	.info_mask_shared_by_type =					\
+		BIT(IIO_CHAN_INFO_SCALE) |				\
+		BIT(IIO_CHAN_INFO_SAMP_FREQ) |				\
+		BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),	\
+	.info_mask_shared_by_type_available =				\
+		BIT(IIO_CHAN_INFO_SAMP_FREQ) |				\
 		BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),	\
 	.scan_index = index,						\
 	.scan_type = {							\
@@ -279,6 +305,7 @@ static const struct iio_chan_spec adxl372_channels[] = {
 };
 
 struct adxl372_state {
+	const struct adxl372_chip_info	*chip_info;
 	int				irq;
 	struct device			*dev;
 	struct regmap			*regmap;
@@ -471,13 +498,14 @@ static int adxl372_set_activity_time_ms(struct adxl372_state *st,
 	int ret;
 
 	/*
-	 * 3.3 ms per code is the scale factor of the TIME_ACT register for
-	 * ODR = 6400 Hz. It is 6.6 ms per code for ODR = 3200 Hz and below.
+	 * The scale factor of the TIME_ACT register depends on the ODR.
+	 * A higher scale factor is used at the maximum ODR and a lower
+	 * one at all other rates.
 	 */
-	if (st->odr == ADXL372_ODR_6400HZ)
-		scale_factor = 3300;
+	if (st->odr == st->chip_info->max_odr)
+		scale_factor = st->chip_info->act_time_scale_us;
 	else
-		scale_factor = 6600;
+		scale_factor = st->chip_info->act_time_scale_low_us;
 
 	reg_val = DIV_ROUND_CLOSEST(act_time_ms * 1000, scale_factor);
 
@@ -501,13 +529,14 @@ static int adxl372_set_inactivity_time_ms(struct adxl372_state *st,
 	int ret;
 
 	/*
-	 * 13 ms per code is the scale factor of the TIME_INACT register for
-	 * ODR = 6400 Hz. It is 26 ms per code for ODR = 3200 Hz and below.
+	 * The scale factor of the TIME_INACT register depends on the ODR.
+	 * A higher scale factor is used at the maximum ODR and a lower
+	 * one at all other rates.
 	 */
-	if (st->odr == ADXL372_ODR_6400HZ)
-		scale_factor = 13;
+	if (st->odr == st->chip_info->max_odr)
+		scale_factor = st->chip_info->inact_time_scale_ms;
 	else
-		scale_factor = 26;
+		scale_factor = st->chip_info->inact_time_scale_low_ms;
 
 	res = DIV_ROUND_CLOSEST(inact_time_ms, scale_factor);
 	reg_val_h = (res >> 8) & 0xFF;
@@ -717,7 +746,7 @@ static int adxl372_setup(struct adxl372_state *st)
 	if (ret < 0)
 		return ret;
 
-	ret = adxl372_set_odr(st, ADXL372_ODR_6400HZ);
+	ret = adxl372_set_odr(st, st->chip_info->max_odr);
 	if (ret < 0)
 		return ret;
 
@@ -777,10 +806,10 @@ static int adxl372_read_raw(struct iio_dev *indio_dev,
 		*val2 = ADXL372_USCALE;
 		return IIO_VAL_INT_PLUS_MICRO;
 	case IIO_CHAN_INFO_SAMP_FREQ:
-		*val = adxl372_samp_freq_tbl[st->odr];
+		*val = st->chip_info->samp_freq_tbl[st->odr];
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
-		*val = adxl372_bw_freq_tbl[st->bw];
+		*val = st->chip_info->bw_freq_tbl[st->bw];
 		return IIO_VAL_INT;
 	}
 
@@ -796,23 +825,17 @@ static int adxl372_write_raw(struct iio_dev *indio_dev,
 
 	switch (info) {
 	case IIO_CHAN_INFO_SAMP_FREQ:
-		odr_index = adxl372_find_closest_match(adxl372_samp_freq_tbl,
-					ARRAY_SIZE(adxl372_samp_freq_tbl),
-					val);
+		odr_index = adxl372_find_closest_match(st->chip_info->samp_freq_tbl,
+						       st->chip_info->num_freqs,
+						       val);
 		ret = adxl372_set_odr(st, odr_index);
 		if (ret < 0)
 			return ret;
-		/*
-		 * The timer period depends on the ODR selected.
-		 * At 3200 Hz and below, it is 6.6 ms; at 6400 Hz, it is 3.3 ms
-		 */
+		/* Recalculate activity time as the timer period depends on ODR */
 		ret = adxl372_set_activity_time_ms(st, st->act_time_ms);
 		if (ret < 0)
 			return ret;
-		/*
-		 * The timer period depends on the ODR selected.
-		 * At 3200 Hz and below, it is 26 ms; at 6400 Hz, it is 13 ms
-		 */
+		/* Recalculate inactivity time as the timer period depends on ODR */
 		ret = adxl372_set_inactivity_time_ms(st, st->inact_time_ms);
 		if (ret < 0)
 			return ret;
@@ -825,9 +848,9 @@ static int adxl372_write_raw(struct iio_dev *indio_dev,
 
 		return ret;
 	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
-		bw_index = adxl372_find_closest_match(adxl372_bw_freq_tbl,
-					ARRAY_SIZE(adxl372_bw_freq_tbl),
-					val);
+		bw_index = adxl372_find_closest_match(st->chip_info->bw_freq_tbl,
+						      st->chip_info->num_freqs,
+						      val);
 		return adxl372_set_bandwidth(st, bw_index);
 	default:
 		return -EINVAL;
@@ -957,24 +980,6 @@ static int adxl372_write_event_config(struct iio_dev *indio_dev, const struct ii
 	return adxl372_set_interrupts(st, st->int1_bitmask, 0);
 }
 
-static ssize_t adxl372_show_filter_freq_avail(struct device *dev,
-					      struct device_attribute *attr,
-					      char *buf)
-{
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	struct adxl372_state *st = iio_priv(indio_dev);
-	int i;
-	size_t len = 0;
-
-	for (i = 0; i <= st->odr; i++)
-		len += scnprintf(buf + len, PAGE_SIZE - len,
-				 "%d ", adxl372_bw_freq_tbl[i]);
-
-	buf[len - 1] = '\n';
-
-	return len;
-}
-
 static ssize_t adxl372_get_fifo_enabled(struct device *dev,
 					  struct device_attribute *attr,
 					  char *buf)
@@ -1142,25 +1147,38 @@ static const struct iio_trigger_ops adxl372_peak_data_trigger_ops = {
 	.set_trigger_state = adxl372_peak_dready_trig_set_state,
 };
 
-static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("400 800 1600 3200 6400");
-static IIO_DEVICE_ATTR(in_accel_filter_low_pass_3db_frequency_available,
-		       0444, adxl372_show_filter_freq_avail, NULL, 0);
-
-static struct attribute *adxl372_attributes[] = {
-	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
-	&iio_dev_attr_in_accel_filter_low_pass_3db_frequency_available.dev_attr.attr,
-	NULL,
-};
+static int adxl372_read_avail(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan,
+			      const int **vals, int *type, int *length,
+			      long mask)
+{
+	struct adxl372_state *st = iio_priv(indio_dev);
 
-static const struct attribute_group adxl372_attrs_group = {
-	.attrs = adxl372_attributes,
-};
+	switch (mask) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		*vals = st->chip_info->samp_freq_tbl;
+		*type = IIO_VAL_INT;
+		*length = st->chip_info->num_freqs;
+		return IIO_AVAIL_LIST;
+	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
+		*vals = st->chip_info->bw_freq_tbl;
+		*type = IIO_VAL_INT;
+		/*
+		 * Bandwidth cannot exceed half the sampling frequency
+		 * (Nyquist), so limit available values based on current ODR.
+		 */
+		*length = st->odr + 1;
+		return IIO_AVAIL_LIST;
+	default:
+		return -EINVAL;
+	}
+}
 
 static const struct iio_info adxl372_info = {
 	.validate_trigger = &adxl372_validate_trigger,
-	.attrs = &adxl372_attrs_group,
 	.read_raw = adxl372_read_raw,
 	.write_raw = adxl372_write_raw,
+	.read_avail = adxl372_read_avail,
 	.read_event_config = adxl372_read_event_config,
 	.write_event_config = adxl372_write_event_config,
 	.read_event_value = adxl372_read_event_value,
@@ -1176,7 +1194,7 @@ bool adxl372_readable_noinc_reg(struct device *dev, unsigned int reg)
 EXPORT_SYMBOL_NS_GPL(adxl372_readable_noinc_reg, "IIO_ADXL372");
 
 int adxl372_probe(struct device *dev, struct regmap *regmap,
-		  int irq, const char *name)
+		  int irq, const struct adxl372_chip_info *chip_info)
 {
 	struct iio_dev *indio_dev;
 	struct adxl372_state *st;
@@ -1192,13 +1210,14 @@ int adxl372_probe(struct device *dev, struct regmap *regmap,
 	st->dev = dev;
 	st->regmap = regmap;
 	st->irq = irq;
+	st->chip_info = chip_info;
 
 	mutex_init(&st->threshold_m);
 
 	indio_dev->channels = adxl372_channels;
 	indio_dev->num_channels = ARRAY_SIZE(adxl372_channels);
 	indio_dev->available_scan_masks = adxl372_channel_masks;
-	indio_dev->name = name;
+	indio_dev->name = chip_info->name;
 	indio_dev->info = &adxl372_info;
 	indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE;
 
diff --git a/drivers/iio/accel/adxl372.h b/drivers/iio/accel/adxl372.h
index 80a0aa9714fc..3ce06609446c 100644
--- a/drivers/iio/accel/adxl372.h
+++ b/drivers/iio/accel/adxl372.h
@@ -10,8 +10,22 @@
 
 #define ADXL372_REVID	0x03
 
+struct adxl372_chip_info {
+	const char *name;
+	const int *samp_freq_tbl;
+	const int *bw_freq_tbl;
+	unsigned int num_freqs;
+	unsigned int act_time_scale_us;
+	unsigned int act_time_scale_low_us;
+	unsigned int inact_time_scale_ms;
+	unsigned int inact_time_scale_low_ms;
+	unsigned int max_odr;
+};
+
+extern const struct adxl372_chip_info adxl372_chip_info;
+
 int adxl372_probe(struct device *dev, struct regmap *regmap,
-		  int irq, const char *name);
+		  int irq, const struct adxl372_chip_info *chip_info);
 bool adxl372_readable_noinc_reg(struct device *dev, unsigned int reg);
 
 #endif /* _ADXL372_H_ */
diff --git a/drivers/iio/accel/adxl372_i2c.c b/drivers/iio/accel/adxl372_i2c.c
index 186d4fe9a556..5d135b1150c8 100644
--- a/drivers/iio/accel/adxl372_i2c.c
+++ b/drivers/iio/accel/adxl372_i2c.c
@@ -20,11 +20,13 @@ static const struct regmap_config adxl372_regmap_config = {
 
 static int adxl372_i2c_probe(struct i2c_client *client)
 {
-	const struct i2c_device_id *id = i2c_client_get_device_id(client);
+	const struct adxl372_chip_info *chip_info;
 	struct regmap *regmap;
 	unsigned int regval;
 	int ret;
 
+	chip_info = i2c_get_match_data(client);
+
 	regmap = devm_regmap_init_i2c(client, &adxl372_regmap_config);
 	if (IS_ERR(regmap))
 		return PTR_ERR(regmap);
@@ -38,17 +40,17 @@ static int adxl372_i2c_probe(struct i2c_client *client)
 		dev_warn(&client->dev,
 		"I2C might not work properly with other devices on the bus");
 
-	return adxl372_probe(&client->dev, regmap, client->irq, id->name);
+	return adxl372_probe(&client->dev, regmap, client->irq, chip_info);
 }
 
 static const struct i2c_device_id adxl372_i2c_id[] = {
-	{ "adxl372" },
+	{ "adxl372", (kernel_ulong_t)&adxl372_chip_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, adxl372_i2c_id);
 
 static const struct of_device_id adxl372_of_match[] = {
-	{ .compatible = "adi,adxl372" },
+	{ .compatible = "adi,adxl372", .data = &adxl372_chip_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, adxl372_of_match);
diff --git a/drivers/iio/accel/adxl372_spi.c b/drivers/iio/accel/adxl372_spi.c
index 39941b519c3b..e96a355bfe67 100644
--- a/drivers/iio/accel/adxl372_spi.c
+++ b/drivers/iio/accel/adxl372_spi.c
@@ -22,24 +22,26 @@ static const struct regmap_config adxl372_spi_regmap_config = {
 
 static int adxl372_spi_probe(struct spi_device *spi)
 {
-	const struct spi_device_id *id = spi_get_device_id(spi);
+	const struct adxl372_chip_info *chip_info;
 	struct regmap *regmap;
 
+	chip_info = spi_get_device_match_data(spi);
+
 	regmap = devm_regmap_init_spi(spi, &adxl372_spi_regmap_config);
 	if (IS_ERR(regmap))
 		return PTR_ERR(regmap);
 
-	return adxl372_probe(&spi->dev, regmap, spi->irq, id->name);
+	return adxl372_probe(&spi->dev, regmap, spi->irq, chip_info);
 }
 
 static const struct spi_device_id adxl372_spi_id[] = {
-	{ "adxl372", 0 },
+	{ "adxl372", (kernel_ulong_t)&adxl372_chip_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(spi, adxl372_spi_id);
 
 static const struct of_device_id adxl372_of_match[] = {
-	{ .compatible = "adi,adxl372" },
+	{ .compatible = "adi,adxl372", .data = &adxl372_chip_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, adxl372_of_match);
-- 
2.43.0

On Sat, 21 Mar 2026 12:04:56 +0200
Antoniu Miclaus <antoniu.miclaus@analog.com> wrote:

> Introduce a chip_info structure to parameterize device-specific
> properties such as ODR/bandwidth frequency tables, activity/inactivity
> timer scale factors, and the maximum ODR value. This refactors the
> driver to use chip_info lookups instead of hardcoded values, preparing
> the driver to support multiple device variants.
> 
> The sampling_frequency and filter_low_pass_3db_frequency available
> attributes are switched from custom sysfs callbacks to read_avail()
> based handling via info_mask_shared_by_type_available. This enforces
> consistent formatting through the IIO framework and makes the values
> accessible to in-kernel consumers.

I'd slightly have preferred that as a precursor patch, but never mind
it's not too bad in here.  So this is more of a comment for 'next
time' than anything to bother fixing for this series.

> 
> The SPI/I2C probe functions are updated to pass a chip_info pointer
> instead of a device name string.
> 
> No functional change intended.
> 
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>